Bill prefers brush and ink and crow quill pens,
but will use other pens under extreme duress (preferably followed by
a hefty check), usually on bristol board, but occasionally on any
suitably defensless surface. The Martian Sand Ship image was done with brush
and ink on Duo-Tone board, which has latent textures printed on
the board that become visible when developers are applied. Many
political cartoonists use this medium. The Frontier cartoon uses Zipatone™, an adhesive backed material for shading.